Diffusion Weighted Imaging (DWI) has the potential for being a safe, cost-effective alternative to ultrasound as a supplemental procedure to mammography for screening the 40%-50% of women with dense breasts to identify women who have suspicious breasts lesions. The investigators have developed two patent-pending methods for improving sensitivity in detection of breast cancer using (DWI): (1) Analyzing ADC gradient at the lesion border, and (2) Enhancing diffusion images to improve differentiation of lesion from background tissue. In the Phase I study, the novel methodologies successfully detected and discriminated a high percentage of breast lesions, without rejecting any cases because of imaging problems or patient motion. In Phase II, the investigators will develop a prototype computer-aided-diagnosis (CAD) system using the novel methodologies and will evaluate performance with a reader study. The primary measurement for detecting breast cancer in DWI is Apparent Diffusion Coefficient (ADC). Other measures of diffusion require Diffusion Tensor Imaging (DTI), an imaging procedure that takes twice as long as DWI and is more difficult to cost-justify. Using standard methodologies, ADC has two critical shortcomings, low sensitivity and high rejection rate due to imaging problems and patient motion, which hinder clinical use of DWI for breast cancer detection. The two innovative methodologies developed in Phase I improved sensitivity and had zero rejection rate in the Phase I feasibility study. Both mammography and ultrasound miss a significant percentage of breast cancers in women with dense breasts. Dynamic Contrast Enhanced (DCE) MRI screening has high sensitivity, but is not recommended for screening women who have a low or moderate risk of breast cancer. The American Cancer Society recommends DCE for breast cancer screening when a women's risk is higher than 20%, a threshold that is not met when high breast density is the only risk factor. The long-range goal of this project is to develop a clinically and commercially viable CAD system for evaluating DWI images which, when used in conjunction with mammography, is able to identify those women with dense breasts who have a breast-cancer risk greater than the 20% ACS threshold for which follow-up DCE screening is cost-justified.